Mechanics Key Terms (SC100)

5. The rate at which an object’s velocity changes. It can be speeding up, slowing down, or changing direction.
7. The maximum speed an object reaches when falling, when air resistance balances weight.
8. A graph showing how distance changes over time; the slope shows speed.
14. How far an object moves. Measured in metres (m).
15. Force = mass × acceleration (F = m × a). A larger force causes more acceleration.
16. The force of gravity acting on an object. Calculated using W = m × g.
17. Forces that are not equal, causing an object to accelerate (change speed or direction).
19. When a force moves an object in the same direction as the force. Calculated by Work = Force × Distance.
20. The force that pulls objects toward Earth (or any other mass). On Earth, it’s about 9.8 N/kg.
22. Forces that are equal in size and opposite in direction, so there is no change in motion.
23. Energy stored in an object due to its height above the ground. GPE = m × g × h.
27. For every action force, there is an equal and opposite reaction force.
28. The upward force from a surface that balances the weight of an object resting on it.
29. An object stays still or moves at the same speed and direction unless an unbalanced force acts on it.
30. The energy an object has because it is moving.
31. The ability to do work or cause change. Measured in joules (J).

1. When an object slows down (a type of negative acceleration).
2. Speed in a specific direction (e.g. 10 m/s north).
3. A type of friction that acts against moving objects through the air.
4. How long something takes. Measured in seconds (s).
6. The amount of matter in an object. Measured in kilograms (kg). Does not change with location.
9. A measure of how hard it is to stop a moving object. Momentum = mass × velocity.
10. A force that resists motion between two surfaces in contact.
11. Stored energy because of an object’s position (e.g. at a height).
12. Energy cannot be created or destroyed; it can only be changed from one form to another.
13. How fast an object moves. Calculated using speed = distance ÷ time.
18. A graph showing how speed changes over time; the slope shows acceleration.
21. The rate at which work is done or energy is used. Power = Work ÷ Time.
24. The straight-line distance and direction from the start point to the end point.
25. A push or pull on an object that can make it move, stop, speed up, slow down, or change direction. Measured in newtons (N).
26. A pulling force carried by a rope, string, or wire.